Some biomarkers for neurological damage are well known. The S100B protein, present in the calcium canal of glial cells, and the Neurological Specific Enolase (NSE), an enzyme that participates in neurological glucolysis are increased in patients with Brain Trauma, cerebral ischemia or bleeding. In older patients with delirium the levels of S100B are also increased, but not the NSE levels. In critical patients the S100B and NSE have been used for delirium and cognitive impairment markers. However, the publications have been contradictories. Most of them find high levels of S100Bin septic and postoperative patients who developed delirium, but in some studies no significant differences have been seen. NSE has not relation with delirium in septic patients, however, after cardiac surgery with extracorporeal circulation both markers, S100B and NSE, are good predictors of delirium and cognitive impairment at 6 months.